1. Field of the Invention
The present invention relates to a torch for TIG welding, CO.sub.2 gas shielded arc welding or the like used for metal welding or cutting.
2. Description of the Related Art
TIG welding, MIG welding, CO.sub.2 gas shielded welding or the like widely used in the related industries usually utilize inert gas to shield arc as well as molten pool (welded zone) from the ambient atmosphere so that the molten metal may be protected from contact with harmful gas and thereby a welded joint of high quality may be obtained.
During operation of such welding, the enterprise is obliged to take an effective preventive measure, particularly for the operation of welding performed within the indoor workshop, in conformity with the regulations so that the operator may be protected from pneumoconiosis (welder's lung) caused by inhaling said metallic fume.
Specifically, the indoor workshop must be provided with general or at least local forced ventilation equipment in order to protect the operator from inevitably inhaling of said metallic fume and more strictly from exposure thereto.
However, it is sometimes difficult to install said forced ventilation equipment in order that the operator can easily move one welded zone to the next zone to be welded and convenience for operation can be ensured. In this case, the operator must wear a dustproof mask during operation of welding.
Regrettably, the dustproof mask imposes the wearer a breathing resistance. Additionally, light-shielding goggles (or spectacles) make it difficult to wear the dustproof mask or to fit the dustproof mask to the operator's face. In consequence, a dustproof effect may be unacceptably deteriorated or the operator's skin may suffer from eczema appearing on a region closely contacted by the dustproof mask. To avoid these problems, the operator often works without wearing of the dustproof mask.
There have already been several welding torches made on experimental basis provided on their outer peripheral walls with suction ports for welding fume as well as inert gas. However, none of these trial torches has been put to practical use for the reason that they are of heavy weight unacceptably for the operator and unable to achieve a desired ventilating effect.
Purpose of utilizing inert gas in the arc welding processes is to substitute the ambient atmosphere present in the vicinity of the molten pool with this inert gas and thereby to obtain a welded joint of high quality. However, so far as the indoor workshop (inclusive of the operation performed within a tank) is concerned, there may be an apprehension that not only a welder but also the other persons working in the proximity of this welder might inhale the metallic fume generated from the molten pool or at least might be exposed to such metallic fume. Additionally, there is a possibility that the inert gas utilized for shielding purpose also might affect the health of the welder if the inert gas is inhaled by the welder.